[Common] Update NCCL submodule to have the fix for MAX_SUPPORTED_TOKENS_PER_RANK

[phu0ngng]

Description

Update NCCL submodule to have the fix for MAX_SUPPORTED_TOKENS_PER_RANK

Type of change

• Documentation change (change only to the documentation, either a fix or a new content)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Infra/Build change
• Code refactoring

Checklist:

• I have read and followed the contributing guidelines
• The functionality is complete
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[greptile-apps]

Greptile Summary

This PR bumps the 3rdparty/nccl submodule to pick up a downstream fix for MAX_SUPPORTED_TOKENS_PER_RANK and reorders the NCCL discovery probe in setup.py to prefer the library the runtime dynamic loader will actually resolve.

• Submodule bump: pointer advanced from 808d2433 to a6b5de08; no TransformerEngine source changes.
• _discover_nccl_home reorder: ldconfig is now consulted before well-known prefixes, and the nvidia-nccl-cu* pip-wheel fallback moves to last place, avoiding ABI mismatches where the build would link against the pip wheel but the loader would resolve the system NCCL at runtime.

Confidence Score: 5/5

Safe to merge; both changes are narrow in scope — a submodule pointer bump and a probe-order reorder in build tooling.

The submodule bump carries an upstream fix and touches no TransformerEngine source. The setup.py reorder is well-reasoned, well-commented, and only affects the build-time NCCL discovery path; it correctly defers the pip-wheel probe to last so the build links against the same library the runtime loader resolves.

No files require special attention.

Important Files Changed

Filename	Overview
3rdparty/nccl	NCCL submodule pointer bumped from 808d2433 to a6b5de08 to pick up the MAX_SUPPORTED_TOKENS_PER_RANK fix.
setup.py	NCCL discovery order in _discover_nccl_home() changed: ldconfig is now consulted before well-known prefixes, and the pip wheel fallback is moved to last; docstring updated to match.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[_discover_nccl_home] --> B{NCCL_HOME env var set?}
    B -- Yes, header found --> C[Return NCCL_HOME]
    B -- Yes, header missing --> D[Warn, continue]
    B -- No --> D
    D --> E{ldconfig -p finds libnccl.so?}
    E -- Yes, nccl.h found at parent --> F[Return ldconfig root]
    E -- No / not found --> G[Probe well-known prefixes]
    G --> H{/opt/nvidia/nccl, /usr/local/nccl, /usr?}
    H -- Found --> I[Return prefix]
    H -- Not found --> J[Probe pip wheel nvidia.nccl]
    J --> K{nvidia.nccl importable & nccl.h present?}
    K -- Yes --> L[Return pip_root]
    K -- No --> M[raise RuntimeError]

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%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
flowchart TD
    A[_discover_nccl_home] --> B{NCCL_HOME env var set?}
    B -- Yes, header found --> C[Return NCCL_HOME]
    B -- Yes, header missing --> D[Warn, continue]
    B -- No --> D
    D --> E{ldconfig -p finds libnccl.so?}
    E -- Yes, nccl.h found at parent --> F[Return ldconfig root]
    E -- No / not found --> G[Probe well-known prefixes]
    G --> H{/opt/nvidia/nccl, /usr/local/nccl, /usr?}
    H -- Found --> I[Return prefix]
    H -- Not found --> J[Probe pip wheel nvidia.nccl]
    J --> K{nvidia.nccl importable & nccl.h present?}
    K -- Yes --> L[Return pip_root]
    K -- No --> M[raise RuntimeError]

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_{Reviews (3): Last reviewed commit: "Merge branch 'main' into update_nccl" | Re-trigger Greptile}

[phu0ngng]

/te-ci L1

[phu0ngng]

/te-ci L1

[phu0ngng]

/te-ci L1